In an unprecedented move, the European Commission is set to block two Bulgarian agencies from using EU funds worth hundreds of millions of euros, reported BBC.
The move is prompted by concerns over corruption and organised crime.
The penalty comes with a set of scathing reports condemning the failure to tackle deep rooted corruption in Bulgaria and its neighbour Romania.
Both countries have been under close supervision since they joined the European Union in 2007.
Eighteen months after it joined the EU as the bloc's poorest member, Bulgaria risks losing millions if not billions in EU aid.
In the toughest terms ever used about a member state, the EU executive says that despite some efforts to fight corruption and organised crime, Bulgaria's institutions look good on paper but do not produce good results in practice.
A series of reports due to be published on Wednesday describe a growing sense of frustration among other EU countries.
The European Commission is now set to block two key Bulgarian agencies from handling EU money.
Romania will escape penalties for now, but the report says reforms there are fragile and it condemns parliament for delaying corruption inquiries involving a former prime minister and other top officials.
Amid widespread wariness about further EU expansion, the message from the European Commission is that unless the newcomers behave they will have to pay the price.